What this site is for
A free retirement calculator that answers one question: do I have enough to retire? What it models, who it is for, and what it deliberately leaves out.
Most people approaching retirement are trying to answer one question, and it is not a complicated one to state: do I have enough?
It is, however, genuinely hard to answer. The money is spread across accounts with different tax treatments and different withdrawal rules. Social Security depends on when you claim it. Required Minimum Distributions start on a date that depends on the year you were born. A pension may or may not keep pace with inflation. And all of it has to be measured against a spending number that is itself only a guess.
This site is a calculator that holds all of that in one place and projects it forward, one year at a time, until you either run out of money or you don’t.
How to start
Open the calculator and work through the guided setup. It asks for your age, when you would like to retire, the accounts you hold and roughly what you expect to spend each year. That is enough to produce a projection.
Everything stays editable afterwards. The setup exists so that a first-time visitor is not confronted with eleven tabs and no idea which one to open; it is not a one-time gate, and re-running it is a reasonable way to change several assumptions at once.
What it models
- Year-by-year balances for pre-tax 401(k), 403(b), 457(b) and TSP, Roth, traditional IRA, HSA, taxable brokerage, pensions and rental property.
- Social Security at a claiming age you choose, indexed to inflation.
- Pensions, with an optional partial COLA, because most are not indexed, and pretending otherwise is the most common way a plan looks fine and isn’t.
- Required Minimum Distributions from your SECURE 2.0 applicable age, which is 73 or 75 depending on your birth year, covering pre-tax and governmental 457(b) balances.
- Taxes on withdrawals, grossed up. If you need $60,000 to spend, the plan withdraws enough that $60,000 survives the tax.
- Monte Carlo simulation over randomised annual returns, so you get a probability that the plan holds rather than a single deterministic number that implies more certainty than anyone has.
- Households where two people retire in different years, each with their own retirement date, RMD clock and claiming age.
- Named scenarios, “retire at 60” against “retire at 65”, compared side by side.
Every figure comes from one projection engine, so the Overview, the RMD tab and the Monte Carlo simulation are all reading the same numbers rather than each computing their own.
What it does not do
Being clear about this matters as much as the feature list:
- It is not advice. It is a model that does exactly what you tell it to. Change the assumed return rate and the answer changes, which is the point.
- It does not model tax brackets, only a single effective rate. That is fine for planning and no substitute for a tax preparer in the year you withdraw.
- It does not know about healthcare before Medicare, beyond whatever you put in your spending figure. The gap between retiring at 60 and turning 65 is real and expensive, and this tool will not remind you about it.
- It does not account for your specific circumstances: a divorce decree, a disability, a business sale, an inheritance. It models the ordinary case.
Your data stays in your browser
There is no signup, no account required, and no server doing the maths. The projection runs in your browser, and everything you enter is stored in that browser’s local storage. Nothing is transmitted anywhere.
That is also why the site needs JavaScript enabled, and why clearing your browser data clears your plan.
There is an optional paid tier that adds cloud sync of the same figures across devices, for people who want to pick up on a phone where they left off on a laptop. Every projection, scenario and Monte Carlo feature is free and always will be. The paid tier adds sync, not maths.
What this blog is for
Mostly, explaining the assumptions.
Any retirement calculator is a pile of assumptions wearing a single number as a disguise, and the useful thing is usually not the number but knowing which assumption it is resting on. So these posts work through them one at a time: what the projection actually assumes, how a household where two people retire in different years is modelled, and more as they come up.
If you would rather watch than read, the app has short narrated walkthroughs of each feature under its Videos tab, and a How It Works tab that explains every formula in plain language.
A standing caveat. Everything here is general information about how retirement projections work, not individualised financial, tax or legal advice. The figures this tool produces are estimates built from assumptions you supply, and they are not predictions.